Wireless signals that are transmitted with more than one transmit antenna or over more than one non-orthogonal spatial channel on the same frequencies are combined in the communication channel. These signals should be separated again in the receiver for proper decoding. Some conventional receivers employ maximum-likelihood (ML) decoding to separate different transmitted signals. These maximum-likelihood decoding techniques are computationally expensive, even for signals transmitted with as few as two transmit antennas. Some other conventional receivers employ minimum-mean-squared error (MMSE) decoding to reduce the amount of computations for separating different transmitted signals. In many situations, MMSE decoding techniques fall significantly short of ML decoding techniques and may result in a significant reduction in performance, especially for a practical wireless communication system.
Thus, there are general needs for receivers and methods of decoding signals transmitted with more than transmit antenna or over more than one spatial channel. There are also needs for receivers and methods of decoding signals with reduced processing. There are also needs for receivers and methods of decoding signals with better performance.